I used 3/4 mdf on my last set of forms and strong back. It is a heavy setup. The MDF is okay for the forms. It takes a staple fine and the true benefit is that it can be faired easily and due to it uniformity it is easy to cut acurately with a handheld jig saw. It does make quite a mess make sure to wear a mask and cut the forms where it is easy to clean up. The strong back should probably be made out of ply, unless you have a biscit joiner to create strong glue joints in the MDF i made mine out of MDF and had to screw it together to reinforce the joints. But it worked okay It just made a hell of a mess routing the rabbets.

Tom

: Planning to build my first kayak soon, and wondering about what to use for
: forms and a strongback. I can buy 4x8 sheets of 3/4" MDF for $20
: locally, and was wondering if this is a reasonable material to use for
: forms. It seems everyone talks about using 1/2" plywood? Form cost
: seems small compared to everything else involved, so I guess a few dollars
: either way for a better material isn't going to break the project. What
: thoughts can you share on the ideal form material? MDF vs MDO vs particle
: board? 3/4" vs 1/2"? I especially like the flatness of MDF, and
: the ease that it takes pencil marks. Conversely, I've always disliked the
: waviness of plywood. I haven't decided on staples/brads vs none, if that
: makes a difference.

: Thanks.

: Mike.